Study Question: What is the association of relative hypotension (degree and duration of MPP deficit) in patients with vasopressor-dependent shock with the incidence of new significant AKI and major adverse kidney events (MAKE)? 

• Mean Perfusion Pressure (MPP) = MAP - CVP
• MAKE-14: composite measure of death, new initiation of RRT, or doubling of serum creatinine from the premorbid level at Day 14
• Basal MPP estimated using pre-illness BP readings in the chart, basal CVP estimated using prior echo findings or estimated mean values

Methods:

• Multicenter, prospective observational cohort study with 302 patients
• Notable exclusion criteria:
  • age < 40, trauma as primary reason for ICU admission, active bleeding, unavailability of at least two preillness BP readings, pregnancy, "any condition specifically requiring a higher or a lower blood pressure target in the view of a treating clinician"

Results:

• for every percentage increase in the time-weighted average MPP deficit, the odds of developing new significant AKI and MAKE-14 increased by 5.6% (95% CI, 2.2–9.1; P = 0.001) and 5.9% (95% CI, 2.2–9.8; P = 0.002), respectively.
• Relationships between the risks of developing new significant AKI or MAKE-14 and the percentage of time spent with a MAP < 65 mm Hg were not statistically significant 

Take-aways:

• Critically ill patients in shock who had higher and longer degrees of relative hypotension compared to their baseline BPs had a higher incidence of adverse kidney outcomes
• Sidenote: also consider venous congestion/volume overload when thinking about end-organ damage (e.g. MPP not just MAP)

References

Panwar R, Tarvade S, Lanyon N, et al. Relative hypotension and adverse kidney-related outcomes among critically ill patients with shock. A multicenter, prospective cohort study. Am J Respir Crit Care Med. 2020;202(10):1407-1418.